Winding group and method for winding paper around a core to make a log

ABSTRACT

A winding group for winding paper around a core to make a log which has in an upstream position, means for supplying glue onto the core, means for transporting and inserting the core provided with glue in a channel defined at the top by an upper winding roller, supplied from above with the paper directed towards the channel, and at the bottom by a cradle member associated downstream with a lower winding roller, the winding group comprising a third oscillating roller arranged above the lower winding roller, the three rollers having axes parallel to one another and perpendicular to the forward movement of the paper and cooperating with one another downstream of the channel to wind the paper around the core to obtain the log, further being provided cyclic means for tearing the paper moving forward on the upper winding roller, in which the means for supplying glue onto the core comprise means for depositing a plurality of circle arcs of glue on at least one outer portion of the core.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority from Italian Patent Application No. MI2008A002314, filed Dec. 23, 2008, the contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention refers to an improved winding group and method for winding paper around a core to make a log.

BACKGROUND OF THE INVENTION

In common machines for winding paper around a core to make a log, for example for domestic use as toilet paper, paper towel and/or similar, it is currently known to use elements that guide the arriving paper and control its first contact and its winding onto a core in order to make a finished log.

In these machines, usually called rewinders, there are rollers that cooperate to wind the log.

In general, in such known machines there are two fixed rollers that determine the winding of the paper in a log of gradually increasing diameter, whereas a third oscillating roller maintains a certain pressure on the log being formed making sure that it is correctly wound in a well-compacted manner.

In order to optimise the production of the aforementioned logs, various devices have been progressively developed that simultaneously, and in synchrony, supply a new core in the rewinding machine and expel the finished log from it.

In such synchronised steps the paper moving forward on a roller is torn by suitable devices so as to define two edges of which the one downstream is called “final edge” and is wound on the finished log, whereas the one upstream is called “initial edge” and is associated with the new core being inserted into the machine.

An example of these known machines is described in patent WO94/21545A1 where a device for tearing the paper is shown that takes care of tearing the paper moving forward inside the machine, i.e. in a point comprised between that in which the core is introduced and that in which the log is expelled.

Alternatively, there are currently other machines on the market in which the devices for tearing the paper take care of tearing the paper moving forward outside of the machine, i.e. in a point upstream of that in which the core is introduced.

Such a machine is described in patent EP1262434A1.

In both of the aforementioned types of rewinding machines as the device for tearing the paper it is foreseen for there to be a rod member rotating or oscillating around a pin and provided with a head for cyclic cooperation with a roller to tear the paper that moves forward on it.

In such machines, at a certain moment, i.e. when a new core is introduced and a finished log is expelled, the head of the rod comes into contact with the roller on which the paper moves forward, stopping it or slowing it down so as to pull the paper tight downstream of the head that tears the paper itself.

In order to ensure a correct winding of the initial edge of paper on the core being introduced into the channel glue is deposited onto the core itself, said glue, as can be easily imagined, holding the initial edge of the paper promoting its winding.

Regarding this, there exist different glue dispensing devices that, as described for example in patent EP0699168, take care of dispensing a line of glue along a generatrix of the core.

However, such known devices have drawbacks linked to the possibility of making the initial edge of paper couple with such a line of glue as soon as possible in the channel.

Indeed, this is desired both to avoid a possible deposit of glue in the channel and to take care of immediately winding the initial edge without generating creases in the paper being wound.

In order to obtain such an edge-glue coupling as described above it is necessary in known machines to foresee devices capable of “timing” the core equipped with glue upstream of the channel.

However, such timing devices make known machines very complex and difficult to make, as well as greatly slowing down the production of the logs.

SUMMARY OF THE INVENTION

The purpose of the present invention is to make a winding method and group for winding paper around a core to make a log capable of solving the aforementioned drawbacks of the prior art in an extremely simple, cost-effective and particularly functional manner.

Another purpose is to make a winding method and group for winding paper around a core to make a log in which the glue is dispensed onto the core upstream of the channel so as to allow a quick coupling with the “initial edge” of paper moving forward on the upper roller.

Yet another purpose is to be able to have a winding method and group for winding paper around a core to make a log in which the timing device of the core equipped with glue outside of the channel is easy to make and does not in any way slow down the production of the logs.

Yet another purpose is to be able to have a winding method and group for winding paper around a core to make a log in which the coupling of the initial edge with the glue is always ensured also in the presence of errors of linearity of the core and/or wearing of the components that thrust the core upstream of the channel.

Yet another purpose is to be able to have a winding method and group for winding paper around a core to make a log in which the “hold” of the initial edge with the glue is greater with respect to known machines.

Yet another purpose is to be able to have a winding method and group for winding paper around a core to make a log in which the amount of glue dispensed is less with respect to known machines.

These purposes according to the present invention are accomplished by making a winding method and group for winding paper around a core to make a log as outlined, respectively, in the claims.

Further characteristics of the invention are highlighted by the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The characteristics and advantages of a winding method and group for winding paper around a core to make a log according to the present invention shall become clearer from the following description, given as an example and not for limiting purposes, referring to the attached schematic drawings, in which:

FIG. 1 shows a schematic side elevation view partially in section of a winding group for winding paper around a core to make a log according to the present invention in a first step of use at the tearing of the paper and the introduction of a new core into the machine;

FIG. 2 shows a schematic side elevation view partially in section of the winding group of FIG. 1 in a subsequent step of use at the coupling of the initial edge with the new core introduced into the machine;

FIG. 3 shows a schematic side elevation view partially in section of the winding group of FIG. 1 in a subsequent step of use at the winding of the paper on the new core introduced into the machine that has received the initial edge;

FIG. 4 is a schematic side elevation view partially in section of another winding group for winding paper around a core to make a log according to the present invention; and

FIG. 5 is a view from below of a core provided with glue according to the present invention.

With reference to the figures, a winding group for winding paper 11′ around a core 11 to make a log 11″ is shown with 10.

DETAILED DESCRIPTION OF THE DRAWINGS

Such a winding group 10 comprises, in an upstream position, means for dispensing glue onto the core 11, means for transporting and introducing a succession of cores 11 equipped with glue one after the other in a channel 12 that, as can be seen in the figures, is defined at the top by an upper winding roller 14, supplied from above with the paper 11′ directed towards the channel 12 itself, and at the bottom by a cradle member 13.

A lower winding roller 15, associated downstream of the cradle member 13, and a third oscillating roller 16 arranged above the lower winding roller 15 are also foreseen.

These aforementioned three rollers 14, 15, 16, having axes parallel to one another and perpendicular to the forward movement of the paper 11′, cooperate with one another downstream of the channel 12 to wind the paper 11′ around the core 11 to make the finished log 11″.

In order to tear the paper 11′ to identify a final edge 50, which must be wound on the finished log 11″, and an initial edge 60, which must be coupled with a new core introduced into the channel 12, there are cyclic means for tearing the paper 11′ moving forward on the upper winding roller 14.

With regard to the dispenser of glue 21 onto the core upstream of the channel 12, it preferably comprises means for depositing a plurality of circle arcs 21 of glue on at least one outer portion of the core 11 so as not to require a particularly precise timing of the core itself 11 upon introduction into the channel 12.

Such a plurality of circle arcs 21 of glue deposited on the core 11 can be seen in FIG. 5.

Indeed, since the glue 21 is distributed along a circle arc, almost independently from its position on the core 11, upon introduction in the channel 12 it will take care of meeting and securely holding the initial edge 60 of the paper 11′ with greater “hold” with respect to a line of glue.

Advantageously, such a greater “hold” allows the amounts of glue 21 dispensed onto the cores 11 to be reduced.

This aspect is extremely advantageous since it also allows a greater margin for error to make up for the fact that the core 11 is not always linear, for the wearing of the components that thrust and time the core 11 upstream of the channel 12.

In the case in which it is still wished to “time” the core 11 provided with glue 21, the group 10 can comprise means for orienting the core 11 comprising an upper abutment plane 61 that at least partially extends from the means for dispensing glue towards the channel 12 above the means for transporting and introducing the core 11 and friction elements 62, preferably knurled.

Such an upper abutment plane 61 and such friction elements 62 impose a controlled rotation upon the core 11 after the supply of glue 21 to arrange it in an optimal position for immediately receiving the initial edge 60 as soon as the core 11 is inserted into the channel 12.

In particular, the means for supplying glue on the core 11 can comprise a container 40 for the glue equipped with an opening 41 oriented upwards and associated with the means for transporting and introducing the core 11 into the channel 12.

In such a container 40 a member 42 is housed that is mobile between a first position for receiving the glue by immersion and a second position for supplying the glue received onto the core 11 moving forward on the transporting and introducing means.

Such a mobile member comprises a plurality of free heads 43 shaped like a convex arc of circle, in which every free head 43 in the first receiving position is immersed in the glue and in the second supplying position it projects from the opening 41 towards the core 11 beyond the means 53 for transporting the core 11 as schematised in FIG. 1.

The transportation means can comprise a plurality of chains each equipped with thrusters 51.

As cyclic means for tearing the paper 11′, synchronised with the supply of a new core and the expulsion of a finished log 11″, a rod member 17 is foreseen rotating or oscillating around a pin 18 and provided with a head 20 for cyclic cooperation with the upper winding roller 14 for tearing the paper 11′ making direct contact with the latter against the upper winding roller 14.

In particular, according to the present invention such a head 20 of the rod member 17, at least near to the upper winding roller 16 and thus during the tearing of the paper 11′, has a greater peripheral speed with respect to that of the upper winding roller 14.

Generally, the head 20 will roughly have a speed that is greater by about 20% with respect to the upper winding roller 14. As can be seen in FIG. 1 such a speed ratio means that the section of paper 11′ to undergo a tightening is exclusively that upstream of the head 20, unlike all rewinders currently known, thus tearing the paper 11′ upstream of the head 20.

In FIG. 1 it is indeed possible to see both the final edge 50, which must be wound on the log 11″, and the initial edge 60 that stays laid out without creases on the upper winding roller 14 upstream of the head 20 since it is not slowed down in any way by the faster head 20.

Advantageously, in this way, since the initial edge 60 is laid out on the upper winding roller 14 without creases, a correct coupling of the initial edge 60 itself with the new core 11 supplied into the channel 12 is ensured.

The way in which such a coupling occurs without the generation of any creases is shown in FIG. 2.

According to a preferred embodiment the rod member 17 cyclically rotates or oscillates around the pin 18 selectively firstly accelerating as it approaches the upper winding roller 14 upon contact with the paper 11′ in order to definitely have a greater speed with respect to that of the upper winding roller 14.

After the paper 11′ is torn, i.e. as it goes away from the upper winding roller 14, it is foreseen for the rod member 17 to decelerate until it stops.

Finally, in order to provide the greatest possible acceleration path of the rod member 17 for a new tearing of the paper 11′, the rod member 17 after the aforementioned stopping can carry out a rotation in the opposite direction, in other words going towards the upper winding roller 14.

According to a preferred embodiment, shown in the figures, the cyclic means for tearing the paper 11′ are arranged upstream of the channel 12 and cooperate with means for keeping the paper 11′ adhering around the upper winding roller 14 acting at least upstream of the channel 12.

Preferably, such means for keeping the paper 11′ act along both an upstream and downstream section of the cyclic tearing means to keep both the initial edge 60, upstream of the head 20, and the final edge 50 adhering around the upper winding roller 14.

In order to provide for keeping the edges 50 and 60 on the upper winding roller 14, the latter comprises a plurality of longitudinal channels 22 arranged according to a circular ring in proximity to its cylindrical outer side surface in which each of the longitudinal channels 22 is placed in communication with the outside through a plurality of holes 23.

Cooperating with such longitudinal channels 22 there is a pair of suctioning shoes 24, for example in the shape of a circular sector, arranged in axis with the roller 14 and fixed facing the opposite heads in which these suctioning shoes 24 are suitable for causing air to be sucked in through the channels 22 comprised between them from the outside towards the inside of the upper winding roller 14.

Thus, in order to ensure that both the initial edge 60, upstream of the head 20, and the final edge 50 adhere around the upper winding roller 14 during their forward movement, the aforementioned suctioning shoes 24 extend on the heads of the upper winding roller 14 both above and below the point of cyclic contact of the head 20 with the external cylindrical surface of the roller 14 itself.

In the depicted example the shoes 24 extend for a sector of about 180°.

The suction through the shoes 24 can be continuous or suitably synchronised with the operation of the group 10 and ensures the transportation of the initial edge 60 adhering to the shell of the roller in the fraction that runs between the tearing of the paper and the insertion of the new core in the channel 12.

The core 11, inserted in the channel 12 in which it is supported by the cradle member 13, receives the initial edge 60 of the paper 11′, which, staying adhering without creases to the surface of the suction roller 14 during the rotation thereof, makes such a coupling optimised.

Indeed, the sucking surface of the upper roller 14 avoids the initial edge 60 of the paper 11′ returning back and the greater speed of the head 20 avoids any accumulation of paper upstream of the head 20 itself.

At the inlet of the channel 12 a thruster 52 can be foreseen rotating around a pin to insert the cores 11 into the channel 12 at the unloading of the finished log 11″ and at the start of a new log to be formed.

Of course, other types of oscillating or rotating thrusters, different to what has been shown as a non-limiting example, could be arranged at the inlet of the channel 12.

The means for dispensing glue onto the core according to the present invention can, for example, be associated with known rewinders in which the tearing of the paper 11′ takes place both inside the channel 12 and upstream of it through a stopping element 17 that slows down the paper 11′ moving forward on the roller 14, like also for other types of rewinders.

As can be imagined, the glue 21 during the journey of the core 11 in the channel 12 holds the initial edge 60, which proceeds on the roller 14 thanks to the suction means, ensuring safe winding of the paper 11′.

Cooperating with the glue 21 it is also possible to foresee means to cause the initial edge 60 to wind onto the core 11 introduced into the channel 12.

Such means to cause winding can comprise means for taking the initial edge 60 away from the upper winding roller 14 arranged at the channel 12 substantially downstream of the cyclic means for tearing said paper 11′ and of the suction shoes 24.

In particular, such means for taking away the initial edge 60 have the purpose of thrusting the initial edge 60 of the paper 11′ towards the lower portion of the channel 12 promoting its firm engagement on the new core 11 equipped with glue 21 that is moving forward in the channel 12.

The core 11 equipped with glue and inserted in the channel 12 receives and thus, as can be seen in FIG. 4, keeps the initial edge 60 of the paper 11′ that, being located between the surface of the core 11 during the rotation thereof and of the cradle 13, avoids any possible deposit of glue 21 on the cradle 13 itself.

The means for taking the initial edge 60 away from the upper winding roller 14 can be of any type, for example of the mechanical type such as cams, but according to a preferred embodiment they comprise a pair of shoes 70 shaped like a circular sector arranged in axis with the roller 14 facing opposite heads at the channel 12 substantially downstream of the cyclic means for tearing the paper 11′.

Such shoes 70 are suitable for causing air to come out through the channels 22 comprised between them and thrusting the initial edge 60 of the paper 11′ downwards into a position comprised between the core 11 moving forward and the cradle 13.

It is very easy to understand how the group 10 object of the invention operates.

Indeed, the winding group 10 for winding paper 11′ around a core 11 to make a log 11″ cyclically carries out the steps of:

a) depositing glue on at least one outer portion of the core 11;

b) transporting and introducing the core 11 provided with glue into a channel 12 defined at the top by an upper winding roller 14 and at the bottom by a cradle member 13 associated downstream with a lower winding roller 15;

c) supplying the paper 11′ from above onto the upper winding roller 14 towards the channel 12;

d) tearing the paper moving forward on the upper winding roller 14 upon insertion of the core 11 provided with glue in the channel 12;

e) winding the paper 11′ around the core 11 to obtain the log 11′ downstream of the channel 12 through cooperation of the upper and lower winding rollers 14, 15 with a third oscillating roller 16 arranged above the lower winding roller 15, in which the step of depositing glue on at least one outer portion of the core 11 comprises the step of:

f) depositing a circle arc 21 of glue on at least one outer portion of the core 11.

Furthermore, the method outlined above can also comprise the step of timing the core 11 equipped with glue 21 through an upper abutment plane 61 and friction elements 62 that impart the controlled rotation of the core 11 upstream of the channel 12.

It has thus been seen that a winding method and group for winding paper around a core to make a log according to the present invention achieves the purposes outlined earlier.

Indeed, the winding method and group for winding paper around a core to make a log of the present invention does not require complex timing devices of the core equipped with glue outside of the channel and also the coupling of the initial edge with the glue is always ensured even in the presence of errors of linearity of the core and/or of wearing of the components that thrust the core upstream of the channel.

Furthermore, in the present invention the “hold” of the initial edge with the glue is greater with respect to known machines with a smaller amount of glue.

The winding method and group for winding paper around a core to make a log of the present invention thus conceived can undergo numerous modifications and variants, all of which are covered by the same inventive concept; moreover, all of the details can be replaced by technically equivalent elements. In practice, the materials used, as well as their sizes, can be whatever according to the technical requirements. 

1. A winding group for winding paper around a core to obtain a log, comprising: in an upstream position means for dispensing glue onto said core, means for transporting and inserting said core provided with said glue into a channel defined at a top by an upper winding roller, supplied from above with said paper directed towards said channel, and at a bottom by a cradle member associated downstream to a lower winding roller, said winding group comprising a third oscillating roller arranged above said lower winding roller, said three rollers having respective axes parallel to each other and perpendicular to the feeding direction of said paper and cooperating with each other downstream of said channel in order to wind said paper around said core to obtain said log, further being provided cyclic means for tearing said paper moving forward on said upper winding roller, wherein said means for dispensing glue onto said core comprise means for depositing circle arcs (21) of glue on at least one outer portion of said core (11).
 2. The winding group of claim 1, wherein said means for dispensing glue onto said core comprise a container for the glue provided with an upwardly directed opening associated with said means for transporting and inserting said core, a movable member being provided housed within said container between a first position for receiving said glue and a second position for dispensing said glue onto said core moving forward on said transport and insertion means; said movable member comprising a plurality of circle arc-shaped convex free heads), each of said free heads being submerged in said glue in said first receiving position and projecting from said opening in said second dispensing position.
 3. The winding group of claim 2, wherein said means for transporting and inserting said core comprise conveyors with pushers.
 4. The winding group of claim 3, wherein conveyors comprise chains parallel to each other on which said pushers are spaced.
 5. The winding group of claim 3, wherein said circle arc-shaped convex free heads extend beyond said conveyors in said second dispensing position.
 6. The winding group of claim 1, wherein said means for transporting and inserting said core comprise a feeder arranged at the beginning of said channel and rotating around a pin in order to insert said core provided with glue inside said channel.
 7. The winding group of claim 1, wherein it comprises means for directing said core cooperating with said means for transporting and inserting said core.
 8. The winding group of claim 1, wherein said means for directing said core comprise an upper abutment plane for said core, which plane develops at least partially from said glue dispensing means towards said channel above said means for transporting and inserting said core and friction elements, said directing means imparting a controlled rotation to said core after said glue is dispensed.
 9. A winding method for winding paper around a core to obtain a log cyclically comprising the steps of: a) depositing glue on at least one outer portion of said core; b) transporting and inserting said core provided with glue into a channel defined at the top by an upper winding roller and at the bottom by a cradle member associated downstream with a lower winding roller; c) supplying said paper from above onto said upper winding roller towards said channel; d) tearing said paper advancing on said upper winding roller upon insertion of said core provided with glue in said channel; and e) winding said paper around said core to obtain said log downstream of said channel through cooperation of said upper and lower winding rollers with a third oscillating roller arranged above said lower winding roller, wherein said step of depositing glue on at least an outer portion of said core comprises the step of f) depositing a plurality of glue circle arcs on at least one outer portion of said core.
 10. The method for winding of claim 9, wherein the method further it also comprises the step of directing said core provided with glue by means of an upper abutment plane and friction elements, upstream of said channel, which impart a controlled rotation to said core. 